Sensitive relay with magnetic toggle



SENSITIVE RELAY WITH MAGNETIC TOGGLE Filed April 4, 1952 2 Sheets-Sheetl CENT-ER LINE OF MAGNEUC VANE RESULTANT INVENTOR.

ERNEST C. WITTKE ATTO EY.

Nov. 1, 1955 E. c. WITTKE SENSITIVE RELAY WITH-MAGNETIC TOGGLE 2Sheets-Sheet 2 Filed April 4, 1952 fZENTER LINE OF c MAGNETIC VANE.

\ CENTER LINEOF 5 *5: MAGNETIC VANE ----RE5ULTANT RESU LTANT-- ERNESTC.WITTKE CENTER LINE oF,/ MAGNETIC VANE 2,722,581 Patented Nov. 1, 1955SENSITIVE RELAY WITH MAGNETIC TOGG LE Ernest Carl Wittke, Bayside, N.Y., assignor to Combustion Engineering, Inc., New York, N. Y., acorporation of Delaware Application April 4, 1952, Serial No. 280,537

11 Claims. (Cl. 20093) My invention relates generally to instrument typerelays and has specific reference to such a relay with means forinsuring a positive contact without chatter.

Instrument type relays have a very sensitive meter movement which isadapted to respond to small electrical currents such as those availablefrom thermocouples, magnetic inductance pickups and the like.

The power that can be developed from such small currents is itselfnecessarily exceedingly small resulting in a small force available tomaintain the contacts of the relay in engagement. Because of this it haslong been a serious problem to obtain a satisfactory electricalconnection between the relay contacts under ordinary operatingconditions. When the contacts are closed with insuflicient force toestablish good electrical contact a point of high resistance isestablished which may result in excessive temperature at this pointcausing said contacts to become welded together. Furthermore with but avery small force maintaining said contacts in engagement considerablechattering will occur during make and break operations and also incidentto any mechanical vibration of the relay.

Various arrangements have been devised in the past in an attempt toovercome the aforementioned difficulties and produce an instrument typerelay which will operate satisfactorily with the small currentsavailable for such purpose. However, all of the prior art devices ofwhich I am aware have had one or more drawbacks making themunsatisfactory for general use as an instrument type relay. They eitheremploy intricate cams, levers, and/ or ratchets which generally have tobe manually reset or they have additional magnetic devices which requiremanual manipulation in order to open the contacts of the relay once theyare closed. Many of these devices are exceedingly cumbersome andexpensive for the result which they are designed to accomplish.

It is therefore the object of my invention to provide an instrument typerelay that is free of the aforementioned difficulties, extremelycompact, highly efficient and relatively cheap to manufacture.

A further object is to provide a completely automatic instrument typerelay having an additional magnetic means associated therewith in such amanner as to provide sure and positive operation of the relay contactswithout chattering.

Other and further Objects and advantages will become apparent as thedescription hereof proceeds.

With the aforementioned objects in view my invention comprises anarrangement, construction and combination of the elements of a relay insuch a manner as to attain the results desired as hereinafter set forthin the following detailed description of the illustrative embodimentdepicted in the accompanying drawings wherein:

Figure l is a diagrammatic representation in the nature of a plan viewof a relay employing my inventive concept;

Figure 2 is a view similar to Fig. 1 with the relay moved to the closedposition;

Figure 3 is a diagrammatic view of the magnetic elements of the relayshowing the effective resultant field relative to the center line of therotatable vane when no current is flowing through the field coils;

Figure 4 is a view similar to Fig. 3 showing the etfective resultantfield when a small current is flowing through the field coils;

Figure 5 is a view similar to Figs. 3 and 4 showing the resultant fieldwith an increased current flowing through the field coils;

Figure 6 is a view similar to Fig. 5 showing the magnetic vane moved toits switch closing position.

The device to be benefitted Referring to the drawings and moreparticularly to Figs. 1 and 2, numeral 1 designates an elongatedgenerally rectangular magnetic vane rotatably mounted about an axis 2perpendicular to the surface thereof and extending centrallytherethrough. A plurality of stops 3 and 5 are arranged to limit therotational movement of said vane within predetermined limits. Hairspring 7 has one end secured to a fixed frame member (not shown) and theother end secured to vane 1 in a manner to urge said vane in a clockwisedirection into engagement with stop 3.

Also secured to said vane is movable contact 9 of an electrical switch,said contact being arranged to engage stationary contact 11 when saidvane is rotated in a counterclockwise direction to its extreme positionwhere it engages stop 5 and to be separated from said stationary contact11 when said vane is moved in a clockwise direction to its extremeportion where it engages stop 3. In order to eliminate any effect uponvane 1 due to connecting movable contact 9 into an electrical circuit,hair spring 7 is utilized as the electrical connection for said movablecontact; said hair spring 7 being secured at one end to said contact andat the other end to lead 13 of a suitable work circuit of which lead 15,secured to contact 11, also forms a portion.

Field coils 1'7, 17' are connected by leads 19 and 21 to a suitabledetecting device (not shown) such as a thermocouple, magnetic inductancepickup or the like. Said coils 17, 17 are positioned adjacent the end ofmagnetic vane 1 but laterally displaced from the longitudinal centerline thereof when said vane occupies a first position wherein contacts9, 11 are open and the vane is in engagement with stop 3 as shown inFigs. 1, 3, 4 and 5. The wiring of coils 17, 17 is such that the flow ofcurrent therethrough in response to activation of the aforementioneddetecting device produces a magnetic field the poles of which areadjacent like poles of said magnetic vane 1 as shown in the drawingswhere N designates a north magnetic pole and S designates a southmagnetic pole. Thus, since like poles repel, the magnetic field createdby field coils 17, 17 tends to rotate said magnetic vane in acounterclockwise direction as viewed in Fig. 1 from said first to asecond position wherein contacts 9, 11 are closed and said vane is inengagement with stop 5 (Figs. 2 and 6).

One meter-type electrical instrument utilizing a permanent magnet rotorin the manner here shown and described is more fully disclosed by U. S.Patent 2,473,939, issued June 21, 1949, to W. B. M. Clark for PolarizedElectromagnet.

The improvement of my invention In accordance with my inventionpermanent magnetic members 23, 23' are also disposed adjacent the endsof said magnetic vane 1. In the illustrative arrangement shown thesemembers 23, 23' are located on the opposite side of the longitudinalcenter line of the vane from said field coils 17, 17' when said vane isin the first or opencontact position in engagement with stop 3 (Figs. 1,3, 4

and 5) and on the same side of said longitudinal center line when saidvane is in the second or closed-contact position in engagement with stop5 (Figs. 2 and 6). Depending on the location of stop 5, otherrelationships are possible.

As in the case of field coils 17, 17, the poles of magnetic members 23,23 are positioned adjacent like poles of said magnetic vane 1 asindicated on the drawings by the N and S designations of magnetic poles.Thus, when vane 1 occupies the first position in engagement with stop 3(contacts 9, 11 then open) said magnetic members 23, 23' are effectiveto urge said vane in a clockwise direction to maintain the vane inengagement with said stop 3; while when vane 1 occupies the secondposition in engagement with stop 5 (contacts 9, 11 then closed) saidmagnetic member 23, 23 are effective to urge said vane in acounterclockwise direction to maintain said vane in engagement with saidstop 5.

in order to facilitate explanation of my improved device, the magneticlines of force represented in Fig. 3 as dotted lines bridging the gapbetween the north (N) and (S) south pole of permanent magnetic members23, 23 and in Figs. 4, 5 and 6 as bridging the gap between the polescreated by current flowing through field coils 17, 17 as well as the gapbetween magnetic members 23, 23 are intended to indicate the respectivestrengths of the individual fields of these two pairs of magneticelements. The dot dash line depicted in Figs. 3, 4, 5 and 6, which islabeled Resultant, indicates the effective resultant magnetic fieldformed by the combination of the aforesaid individual fields.

How improved relay operates My invention thus provides a magnetic togglecomprised of the added permanent magnet members 23 and 23 which arecoordinated with the conventional elements of the relay in the uniquemanner just described. The operation of the so-improved relay will bestbe understood by referring to Figs. 3 to 6, inclusive. With coils 17, 17and magnetic elements 23, 23 disposed as shown in the drawings, withlike magnetic poles adjacent each other, an cifective resultant magneticfield is created somewhere between the individual fields of said coilsand said magnetic elements respectively, depending upon the strength ofthe individual fields, which resultant field is effectively of greaterstrength than either of said individual fields. However, with no currentflowing through field coils 17, 17', as represented by Fig. 3, themagnetic field developed across the gap of magnetic members 23, 23 isthe sole field acting on vane 1, wherefore the effective resultant fieldcoincides with and is of equal strength to the field produced by saidmagnetic members 23, 23' as clearly indicated in said Fig. 3. Underthese circumstances the rotative force, illustrated as F in Fig. 3,acting on magnetic vane 1 due to said magnetic field urges said vane ina clockwise direction into engagement with stop 3.

As the current is raised from zero in coils 17, 17 the effectiveresultant magnetic field is rotated in a clockwise direction. Fig. 4shows the position of said resultant field when the current flowingthrough coils 17, 17' is insufiicient to effect a counterclockwiserotation of magnetic vane 1. t will be observed that under theseconditions the effective resultant field has not been rotated past thelongitudinal center line of magnetic vane 1. Therefore the magneticforce (indicated as F in Fig. 4) tending to rotate said magnetic vane,although greatly reduced from that present under the conditions depictedin Fig. 3, still urges said magnetic vane in a clockwise direction intoengagement with stop 3.

However, as the current flowing through coils 17, 17 continues toincrease, the effective resultant field is further rotated in aclockwise direction and at a predetermined point passes the longitudinalcenter line of magnetic vane l (which may be designated dead center), atwhich time the direction of the rotative force acting on magnetic vane 1is reversed causing said vane to quickly rotate its full distance oftravel in the counterclockwise direction to the switch closing positionin engagement with stop 5. This result is best shown in Figs. 5 and 6wherein F and F, respectively, represent the aforementioned rotativeforce acting on said vane.

Once said vane 1 starts to move in a counterclockwise direction it willcontinue this movement until contacts 911 are closed and stop 5 isengaged since the moment acting on said vane to produce saidcounterclockwise rotation increases more rapidly than thespring-produced moment (from element 7) opposing said rotation. This isdue to the fact that as the vane moves in a counterc1ockwise directionit is approaching a position where the longitudinal axis of said vane isnormal to the effective resultant magnetic field causing the movement ofsaid vane and since the component of the force of said resultantmagnetic field acting to urge said vane in a counterclockwise directionis greatest when the longitudinal axis of said vane is normal to saidresultant field it follows that said force component is increased asthis relationship is approached. This is evidenced in the drawings byvectorially representing F (Fig. 5) as being greater force than P" (Fig.4) with the same current flowing through coils 17, 17'.

It will be noted that when magnetic vane 1 is in engagement with stop 5the effect of the magnetic field produced by magnetic members 23, 23' issuch as to urge said vane into continued engagement with said stop 5.However, the force thus produced by said magnetic members 23, 23' is, ofitself, insutficient to overcome the force of hair spring 7 urging saidvane in a clockwise direction. Therefore when the current in coils 17,17 falls below a predetermined value, at which point the force tendingto maintain magnetic vane 1 in engagement with stop 5 is insufficient toovercome the force of said spring, said magnetic vane will quicklyrotate in a clockwise or contact-opening direction into engagement withstop 3.

Once said clockwise rotation is initiated by spring 7 it will continueat an increasing rate until vane 1 contacts said stop 3. This is due toa reversal of the effect hereinbefore described with respect to thecounterclockwise rotation of said vane; i. e., as the vane moves in aclockwise direction the angularity between the longitudinal axis of thevane and the effective resultant magnetic field decreases, wherefore theforce component produced by said effective resultant magnetic field andwhich acts normal to said longitudinal axis to urge said vane in acounterclockwise direction is also decreased. After said vane has moveda predetermined distance in said clockwise direction the longitudinalaxis of magnetic vane 1 will override the effective resultant fieldproduced by field coils 17, 17' and magnetic members 23, 23, whereuponthe direction of the rotative force upon said vane produced by saideffective field will reverse thereby aiding spring 7 in returning vane 1to its switch opening position in engagement with stop 3.

The amount of current flowing through field coils 17, 17 that isrequired to operate the improved relay can be varied within wide limitssince said current is dependent upon the number of windings in saidcoil, the strength of the magneitc field produced by magnetic members23, 23' and the strength of spring 7.

It will thus be seen that I have provided an instrument type magneticrelay which will make and break without chattering and which has aneffective force pressing the contacts of the relay (here shown at 9, 11)into engagement, when said relay is in the closed position, that isgreater than the force capable of being developed solely by the smallcurrent which motivates the actuation of said relay.

While I have shown and described a preferred embodiment of my magnetictoggle improvement it is to be understood that such is merelyillustrative and not restrictive and that variations and modificationsmay be made therein without departing from the spirit and scope of theinvention. I therefore do not wish to be limited to the precise detailsset forth but desire to avail myself of such changes and alterations asfall within the purview of my invention.

What I claim is:

1. In a relay of the type described, a pivotally mounted polarizedmagnetic vane, switch means associated with said vane and arranged to beopen when said vane is in a first position and closed when said vane isin a second position, means biasing said vane to one of said positions,field coil means disposed adjacent said vane in a manner so that thepoles of the magnetic field created by current flowing through saidfield coil means in a predetermined direction are adjacent like poles ofsaid vane and laterally displaced therefrom in such a manner as to urgesaid vane when in said one position for rotation to the other of saidpositions, additional magnetic means positioned adjacent said vane withthe poles thereof disposed adjacent like poles of said vane butlaterally and outwardly displaced therefrom in such a manner as to urgesaid vane when in said one position for rotation to said one position.

2. In a relay of the type described, a pivotally mounted polarizedmagnetic vane, switch means associated with said vane and arranged to beopen when said vane is in a first position and closed when said vane isin a second position, stop means for limiting the movement of said vaneto within a range defined by said two positions, means biasing said vaneto one of said positions, coil means disposed adjacent said vane in amanner so that the poles of the magnetic field created by currentflowing through said coil means in a predetermined direction areadjacent like poles of said vane and laterally displaced therefrom whensaid vane is in said one position so as to urge said vane for movementfrom said one to the other of said positions, and permanent magneticmeans also associated with said vane with the poles thereof disposedadjacent like poles of said vane but laterally and outwardly displacedtherefrom in such a manner as to urge said vane when in said oneposition for rotation in said one position.

3. An instrument type electrical relay comprising a substantiallyrectangular polarized magnetic vane rotatable about a centrally disposedtransverse axis, said vane having electrical switch means operativelyassociated therewith and being adapted to rotate from a first positionwhere said switch is open to a second position where said switch isclosed; means biasing said vane to said first or open-switch position;stop means for limiting the rotational movement of said vane to within arange defined by said two positions; field coil means disposed adjacentsaid vane in a manner so that the poles of the magnetic field created bycurrent flowing therethrough in a predetermined direction are adjacentlike poles of said magnetic vane and displaced laterally of thelongitudinal center line of said vane in a manner to urge said vane fromsaid first or switch-open position to said second or closedswitchposition; and permanent magnetic means associated with said vane, thepoles of said magnetic means being disposed adjacent like poles of saidvane but located on opposite sides of the longitudinal center line ofsaid vane from the poles created by said field coil when said vane is insaid first position whereby said magnetic means opposes initial rotationof said vane from said first or opencontact position.

4. An instrument type electrical relay comprising a substantiallyrectangular polarized magnetic vane rotatable about a centrally disposedtransverse axis, said vane having electrical switch means operativelyassociated therewith and being adapted to rotate from a first positionwhere said switch is open to a second position where said switch isclosed; spring means biasing said vane to said first position andforming one of the electrical leads for said switch; stop means forlimiting the rotational movement of said vane to within a range definedby said two positions; field coil means disposed adjacent said vane in amanner so that the poles of the magnetic field created by currentflowing therethrough in a predetermined direction are adjacent likepoles of said magnetic vane and displaced laterally of the longitudinalcenter line of said vane in a manner to urge said vane from said firstor openswitch position to said second or closed-switch position; andpermanent magnetic means associated with said vane, the poles of saidmagnetic means being disposed adjacent like poles of said vane butlocated on opposite sides of the longitudinal center line of said vanefrom the poles created by said field coil when said vane is in saidfirst position and on the same side of said longitudinal center linewhen said vane is in said second position whereby said magnetic meansopposes initial rotation of said vane from said first or open-switchposition but once rotation has advanced beyond a given intermediatepoint then aids further rotation of the vane into said second orclosedswitch position.

5. An instrument type electrical relay comprising an elongated polarizedmagnetic vane rotatable in a predetermined plane about a centrallydisposed transverse axis; switch means having a movable contactconnected to said vane and arranged to be open when said vane is in afirst position and closed when said vane is in a second position; meansbiasing said vane to said first or open-contact position; field coilmeans disposed adjacent said vane so that the poles of the magneticfield created by current flowing therethrough in a predetermineddirection are located in said predetermined plane and are adjacent likepoles of said magnetic vane but displaced laterally of the longitudinalaxis thereof in a manner to urge said vane from said first to saidsecond or closed-contact position; and additional magnetic meansassociated with said vane comprising permanent magnetic members withpoles positioned in said predetermined plane adjacent like poles of saidmagnetic vane, said permanent magnetic members being fixedly disposed ata location where the effect of the magnetic field thereof is to opposethe rotation of said vane from said first to said second position whensaid vane occupies said first or open-contact position and from saidsecond to said first position when said vane occupies said second orclosed-contact position.

6. An instrument type electrical relay comprising a rotatably mountedpolarized magnetic vane having electrical switch means operativelyassociated therewith, said vane being adapted to rotate from a firstposition Where said switch is open to a second position where saidswitch is closed, first magnetic means positioned adjacent said vane ina manner so that the poles of the magnetic field created thereby areadjacent like poles of the vane and laterally displaced therefrom insuch a manner as to urge the vane when in one of said positions forrotation to the other position, second magnetic means positionedadjacent said vane so that the poles of the magnetic field createdthereby are adjacent like poles of the vane and laterally and outwardlydisplaced therefrom in such a manner as to oppose rotation of the vaneto the other of said positions when in said one position, the magnitudeof the magnetic field of said first magnetic means which acts upon saidvane being variable and being related to said second magnetic means sothat upon exceeding a predetermined value the resultant force actingupon said vane will effect rotation of said vane from said first to saidsecond position.

7. In an instrument type electrical relay a polarized magnetic vanerotatable about a transverse axis, means limiting the angular movementof the vane to and from first and second positions spaced apredetermined angular distance apart, a first polarized magnetic meansof variable magnitude positioned adjacent an end of the vane with likepoles of the magnetic means and the vane being adjacent, said magneticmeans being displaced laterally of said vane when it is in one of itsextreme positions in a manner so that the repulsion force of saidadjacent like poles urges the vane from said one to the other of saidpositions, additional polarized magnetic means positioned adjacent anend of the vane with like poles of this magnetic means and the vanebeing adjacent, the second mentioned magnetic means being displacedlaterally and outwardly of said vane when it is in its one position in amanner so the repulsion force of said adjacent like poles urges the vanetoward said one position.

8. Apparatus as defined in claim 7 wherein the first mentioned magneticmeans comprises a coil and the second mentioned magnetic means comprisesa permanent magnet.

9. An apparatus as defined in claim 7 wherein the second mentionedmagnetic means is laterally displaced with respect to the vane when thevane is in its other position opposite to its lateral displacement withrespect to the vane when the vane is in its one position.

10. In a relay of the type described a pivotally mounted polarizedmagnetic vane, switch means associated with said vane and arranged to beopen when said vane is in a first position and closed when said vane isin a second position, field coil means disposed adjacent said vane in amanner so that the coil means generates upon energization a magneticfield directed at an angle to the magnetic field of the vane with likepoles of said fields being adjacent so as to create a turning force onthe vane to urge said vane to said second position when in said oneposition, additional magnetic means adjacent said vane and generating amagnetic field directed at an angle to the magnetic field of the vanewith like poles of these fields being adjacent so as to create a turningforce on the vane to urge said vane to said one position when in saidone position.

11. A relay as defined in claim 10 wherein the magnetic field of theadditional magnetic means is directed at an angle to the magnetic fieldof the vane when the vane is in said second position so as to create aturning force tending to urge said vane to said second position.

References Cited in the file of this patent UNITED STATES PATENTS1,675,919 Babcock July 3, 1928 1,743,478 Pratt Jan. 14, 1930 1.818.170Stalder Aug. 11, 1931 1,837,188 Keller Dec. 22, 1931 1,901,443 GarvinMar. 14, 1933 1,951,409 Havenner et a1 Mar. 20, 1934 2 254,411 Ashworthet a1 Sept. 2, 1941 2,298,573 Little Oct. 13, 1942 2,437,726 Davis Mar.16, 1948 FOREIGN PATENTS 118,575 Australia May 31, 1944

